Events are also generated:• whenever any setting in the IED is changed.The internal events are time tagged with a resolution of 1 ms and stored in a list.The list can store up to 40 events. The list is based on the FIFO principle, that is,when it is full, the oldest event is overwritten. The list contents cannot be modified,but the whole list can be cleared using the Reset menu in the LHMI.The list of internal events provides valuable information, which can be used duringcommissioning and fault tracing.The information can, in addition to be viewed on the built in HMI, also be retrievedwith the aid of a PC with PCM600 installed and by using the Event MonitoringTool. The PC can either be connected to the front port, or to the port at the back ofthe IED.20.3 Change lock CHNGLCK GUID-B48775D0-ACF0-49C6-A7F6-69AF37F1C68F v120.3.1 Application GUID-51EEC9C7-8ECF-4546-BC26-326861654340 v4Change lock function CHNGLCK is used to block further changes to the IEDconfiguration once the commissioning is complete. The purpose is to make itimpossible to perform inadvertent IED configuration and setting changes.However, when activated, CHNGLCK will still allow the following actions thatdoes not involve reconfiguring of the IED:• Monitoring• Reading events• Resetting events• Reading disturbance data• Clear disturbances• Reset LEDs• Reset counters and other runtime component states• Control operations• Set system time• Enter and exit from test mode• Change of active setting groupThe binary input controlling the function is defined in ACT or SMT. TheCHNGLCK function is configured using ACT.LOCK Binary input signal that will activate/deactivate the function, defined in ACT orSMT.Section 20 1MRK 505 393-UEN BSecurity400 Line differential protection RED650 2.2 IECApplication manual
